Transceiver Front-End

ABSTRACT

A transceiver front-end of a communication device is disclosed. The transceiver front-end is connectable to a signal transmission and reception arrangement adapted to transmit a transmit signal having a transmit frequency and to receive a receive signal having a receive frequency, to a transmitter adapted to produce the transmit signal, and to a receiver adapted to process the receive signal. The transceiver front-end comprises at least one of a transmit frequency blocking arrangement and a receive frequency blocking arrangement. The transmit frequency blocking arrangement has a blocking frequency interval associated with the transmit frequency and a non-blocking frequency interval associated with the receive frequency, and is adapted to block passage of transmit frequency signals between the signal transmission and reception arrangement and the receiver. The receive frequency blocking arrangement has a blocking frequency interval associated with the receive frequency and a non-blocking frequency interval associated with the transmit frequency, and is adapted to block passage of receive frequency signals between the signal transmission and reception arrangement and the transmitter. At least one of the transmit frequency blocking arrangement and the receive frequency blocking arrangement comprises a network of passive components comprising at least one transformer and a frequency translated impedance adapted to have a higher impedance value in the blocking frequency interval than in the non-blocking frequency interval.

TECHNICAL FIELD

The present invention relates generally to the field of transceiverfront-ends for communication devices. More particularly, it relates totransceiver front-ends providing isolation between a transmitter and areceiver.

BACKGROUND

In transceivers for frequency division duplex (FDD) communication (e.g.a transceiver of a cellular radio equipment), the receiver typicallyexperience strong interference signals from the transmitter of the sametransceiver.

The interference signal from the transmitter has a carrier frequency atduplex distance from the carrier frequency of the receive signal. Atypical duplex distance is small compared to the carrier frequencies.Typically, the duplex distance may be less than 100 MHz while thecarrier frequencies may, for example, be somewhere between 700 MHz and 3GHz.

To be able to operate with required performance (e.g. achieving goodsensitivity), the receiver should preferably be shielded (or isolated)from the interference from the transmitter of the transceiver, both fromtransmitter signals at transmit frequency and transmitter generatedinterference at receive frequency. It is also desirable that thetransmitter is shielded (or isolated) from the received signals. Examplereasons include that as much of the received energy as possible shouldbe transferred to the receiver for optimal receiver performance and thatreceived signals occurring at the transmitter output may causeinterference to the signal to be transmitted.

Such isolation is typically achieved by off-chip acoustic wave duplexfilters (duplexers). A drawback with duplexers is that they aretypically expensive. They are also bulky which increases the size of atransceiver implementation. Duplexers are also fixed in frequency, whichnecessitates several duplexers to be used if several frequency bands areto be supported. These problems are becoming more pronounced as thenumber of frequency bands to be supported by a communication device isincreased.

Therefore, there is a need for integrated solutions that provideisolation between a transmitter and a receiver.

A typical on-chip isolation implementation is based on cancellation ofthe interferer signal. To achieve perfect cancellation of transmitsignals at the receiver input symmetry is necessary, and the circuitrequires a dummy load that equals the antenna impedance both at thereceive frequency and at the transmit frequency. If the antennaimpedance is complex (inductive or capacitive) and/or varies over time(e.g. due to frequency changes and/or changing antenna surroundings),implementation of a perfect cancellation becomes cumbersome.Furthermore, at least 3 dB of the power of receive and transmit signalswill be lost in the dummy load.

US 2011/0064004 A1 discloses an radio frequency (RF) front-endcomprising a power amplifier (PA), a noise-matched low-noise amplifier(LNA), a balance network, and a four-port isolation module. Theisolation module isolates the third port from the fourth port to preventstrong outbound signals received at the third port from saturating theLNA coupled to the fourth port. Isolation is achieved via electricalbalance.

Similarly as described above, a drawback of this solution is that thebalance network needs to track impedance changes in the antenna duringoperation to enable sufficient isolation. The impedance needs to betracked at both receive frequency and transmit frequency simultaneously.Thus, the implementation is sensitive and complex. A further drawback ofthis solution is that at least 3 dB of the power of receive and transmitsignals will be lost due to the matched impedance of the balancenetwork.

Therefore, there is a need for alternative and improved integratedsolutions that provide isolation between a transmitter and a receiver.

SUMMARY

It should be emphasized that the term “comprises/comprising” when usedin this specification is taken to specify the presence of statedfeatures, integers, steps, or components, but does not preclude thepresence or addition of one or more other features, integers, steps,components, or groups thereof.

It is an object of some embodiments to obviate at least some of theabove disadvantages and to provide improved integrated solutions thatprovide isolation between a transmitter and a receiver.

According to a first aspect, this is achieved by a transceiver front-endof a communication device. The communication device may be a wireless orwired communication device.

According to the first aspect, the transceiver front-end is connectable,at a signal transmission and reception arrangement node, to a signaltransmission and reception arrangement adapted to transmit a transmitsignal having a transmit frequency and to receive a receive signalhaving a receive frequency. Examples of signal transmission andreception arrangements include an antenna, a group of antennas, and acable.

The transceiver front-end is also connectable, at one or moretransmitter nodes, to a transmitter adapted to produce the transmitsignal, and, at one or more receiver nodes, to a receiver adapted toprocess the receive signal.

The transceiver front-end comprises one or both of a transmit frequencyblocking arrangement and a receive frequency blocking arrangement.

If the transceiver front-end comprises a transmit frequency blockingarrangement it is connected to the signal transmission and receptionarrangement node and at least one of the receiver nodes. The transmitfrequency blocking arrangement has a blocking frequency intervalassociated with the transmit frequency and a non-blocking frequencyinterval associated with the receive frequency, and is adapted to blockpassage of transmit frequency signals between the signal transmissionand reception arrangement and the receiver. The transmit frequency maybe comprised in the blocking frequency interval and the receivefrequency may be comprised in the non-blocking frequency interval.

If the transceiver front-end comprises a receive frequency blockingarrangement it is connected to the signal transmission and receptionarrangement node and at least one of the transmitter nodes. The receivefrequency blocking arrangement has a blocking frequency intervalassociated with the receive frequency and a non-blocking frequencyinterval associated with the transmit frequency, and is adapted to blockpassage of receive frequency signals between the signal transmission andreception arrangement and the transmitter. The receive frequency may becomprised in the blocking frequency interval and the transmit frequencymay be comprised in the non-blocking frequency interval.

Thus, the transmitter is connectable to the signal transmission andreception arrangement node via the receive frequency blockingarrangement and the receiver is connectable to the signal transmissionand reception arrangement node via the transmit frequency blockingarrangement.

At least one of the transmit frequency blocking arrangement and thereceive frequency blocking arrangement comprises a network of passivecomponents comprising at least one transformer and a frequencytranslated impedance adapted to have a higher impedance value in theblocking frequency interval than in the non-blocking frequency interval.

In some embodiments, both of the transmit frequency blocking arrangementand the receive frequency blocking arrangement comprise a network ofpassive components and a frequency translated impedance. In otherembodiments, one of the transmit frequency blocking arrangement and thereceive frequency blocking arrangement comprises another structure,which may, for example, be comprised in the transceiver front-end orimplemented as a separate module. Examples of other structures include acapacitance-inductance network, and an arrangement with a bank ofsurface acoustic wave (SAW) filters and an antenna switch. Otherexamples of structures include an arrangement with a network of passivecomponents and a frequency selective filter.

In some embodiments, the frequency translated impedance may comprise afrequency selective impedance, a clock signal provider adapted toprovide a clock signal, and a mixer adapted to translate the frequencyselective impedance by mixing it with the clock signal. The clock signalprovider may be a clock signal source such as a clock signal generator,or the clock signal provider may be a clock signal input port of thefrequency translated impedance. Thus, a clock signal generator may ormay not be comprised in the frequency translated impedance. The mixermay comprise a single mixer or a set of mixers (e.g. anIQ-mixer—in-phase/quadrature mixer). In some embodiments, the clocksignal may be a 4-phase IQ-signal and the mixer may be an IQ-mixer.

The frequency translated impedance of the receive frequency blockingarrangement may be adapted to have a higher impedance value at thereceive frequency than at the transmit frequency. The frequencytranslated impedance of the transmit frequency blocking arrangement maybe adapted to have a higher impedance value at the transmit frequencythan at the receive frequency.

According to some embodiments, the signal transmission and receptionarrangement node is connected to a first node of a first side of thetransformer of the receive frequency blocking arrangement, the frequencytranslated impedance of the receive frequency blocking arrangement is afirst frequency translated impedance and is connected to a second nodeof the first side of the transformer of the receive frequency blockingarrangement, and a first node of the one or more transmitter nodes isconnected to a first node of the second side of the transformer of thereceive frequency blocking arrangement.

The receive frequency blocking arrangement may comprise a secondfrequency translated impedance connected to the first node of the secondside of the transformer of the receive frequency blocking arrangementaccording to some embodiments.

The second node of the second side of the transformer of the receivefrequency blocking arrangement may be connected to one or more of athird frequency translated impedance and a second node of the one ormore transmitter nodes. Alternatively, the second node of the secondside of the transformer of the receive frequency blocking arrangementmay be connected to ground.

In some embodiments, the frequency selective impedance of the receivefrequency blocking arrangement may be an impedance having higherimpedance value at frequencies not exceeding a first threshold than atfrequencies exceeding the first threshold and the clock signal may havethe receive frequency.

In some embodiments, the frequency selective impedance of the receivefrequency blocking arrangement may be an impedance having higherimpedance value at frequencies exceeding a second threshold than atfrequencies not exceeding the second threshold and the clock signal mayhave the transmit frequency.

In some embodiments, the frequency selective impedance of the receivefrequency blocking arrangement may be an impedance having higherimpedance value at frequencies in a first interval than at frequenciesnot in the first interval and the clock signal may have the transmitfrequency.

According to some embodiments, the signal transmission and receptionarrangement node is connected to a first node of a first side of thetransformer of the transmit frequency blocking arrangement, thefrequency translated impedance of the transmit frequency blockingarrangement is a fourth frequency translated impedance and is connectedto a second node of the first side of the transformer of the transmitfrequency blocking arrangement, and a first node of the one or morereceiver nodes is connected to a first node of the second side of thetransformer of the transmit frequency blocking arrangement.

The transmit frequency blocking arrangement may comprise a fifthfrequency translated impedance connected to the first node of the secondside of the transformer of the transmit frequency blocking arrangementaccording to some embodiments.

The second node of the second side of the transformer of the transmitfrequency blocking arrangement may be connected to one or more of asixth frequency translated impedance and a second node of the one ormore receiver nodes. Alternatively, the second node of the second sideof the transformer of the transmit frequency blocking arrangement may beconnected to ground.

In some embodiments, the frequency selective impedance of the transmitfrequency blocking arrangement may be an impedance having higherimpedance value at frequencies not exceeding a third threshold than atfrequencies exceeding the third threshold and the clock signal may havethe transmit frequency.

In some embodiments, the frequency selective impedance of the transmitfrequency blocking arrangement may be an impedance having higherimpedance value at frequencies exceeding a fourth threshold than atfrequencies not exceeding the fourth threshold and the clock signal mayhave the receive frequency.

In some embodiments, the frequency selective impedance of the transmitfrequency blocking arrangement may be an impedance having higherimpedance value at frequencies in a second interval than at frequenciesnot in the second interval and the clock signal may have the receivefrequency.

In some embodiments the transmit frequency blocking arrangement maycomprise another structure such as a capacitance-inductance network asmentioned above. In one of these embodiments, the transmit frequencyblocking arrangement may comprise a first inductance connected betweenthe signal transmission and reception arrangement node and the receivefrequency blocking arrangement, a capacitance connected to the signaltransmission and reception arrangement node at a first node and adaptedto form a matching network (e.g. an L-matched network) for transmitsignals with the first inductance, and a second inductance connectedbetween a second node of the capacitance and a first node of the one ormore receiver nodes and adapted to form a series resonance circuit forreceive signals with the capacitance. The transmit frequency blockingarrangement may also comprise a frequency translated impedance connectedto the second node of the capacitance and comprising a frequencyselective impedance having higher impedance value at frequencies notexceeding a fifth threshold than at frequencies exceeding the fifththreshold, a clock signal provider adapted to provide a clock signalhaving the receive frequency and a mixer adapted to translate thefrequency selective impedance by mixing it with the clock signal.

A second aspect is a transceiver comprising the transceiver front-end ofthe first aspect, the transmitter and the receiver. The transceivercomprises the transmit frequency blocking arrangement and the receivefrequency blocking arrangement, either as part of the transceiverfront-end or one or more separate components (if the transceiverfront-end only comprises one of them). The transceiver may furthercomprise the signal transmission and reception arrangement.

A third aspect is a (wireless or wired) communication device comprisingthe transceiver of the second aspect.

According to a fourth aspect, a method is provided of blocking transmitfrequency signals from passage between a signal transmission andreception arrangement and a receiver of a communication device. Themethod comprises constructing a frequency translated impedancecomprising a frequency selective impedance, a mixer and a clock signalprovider, wherein the frequency translated impedance has a higherimpedance value at the transmit frequency than at the receive frequency.The method further comprises connecting the signal transmission andreception arrangement to a first node of a first side of a transformerand the receiver to a first node of a second side of the transformer,and connecting the frequency translated impedance to a second node ofthe first side of the transformer.

According to a fifth aspect, a method is provided of blocking receivefrequency signals from passage between a signal transmission andreception arrangement and a transmitter of a communication device. Themethod comprises constructing a frequency translated impedancecomprising a frequency selective impedance, a mixer and a clock signalprovider, wherein the frequency translated impedance has a higherimpedance value at the receive frequency than at the transmit frequency.The method further comprises connecting the signal transmission andreception arrangement to a first node of a first side of a transformerand the transmitter to a first node of a second side of the transformer,and connecting the frequency translated impedance to a second node ofthe first side of the transformer.

In some embodiments, the second, third, fourth and fifth aspects mayadditionally have features identical with or corresponding to any of thevarious features as explained above for the first aspect.

An advantage of some embodiments is that a possibility to implement anintegrated solution for isolation between a transmitter and a receiveris provided.

Another advantage of some embodiments is that power loss due to a dummyload is avoided.

A further advantage with some embodiments is that matching of a dummyload to antenna impedance is avoided.

Yet a further advantage with some embodiments is that tracking ofchanging antenna impedance is not necessary.

Some embodiments provide solutions for isolation between a transmitterand a receiver that are simple and area efficient (e.g. two transformersand two frequency translated impedances). Furthermore, the solutionsaccording to some embodiments provide isolation while having low powerconsumption.

The isolation solutions provided by some embodiments are easily tunabledue to the frequency translated impedance structure (changing the clockfrequency fed to the mixer will tune the blocking arrangement to adesired frequency range).

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects, features and advantages will appear from the followingdetailed description of embodiments, with reference being made to theaccompanying drawings, in which:

FIG. 1 is a schematic drawing illustrating a prior art transceiverarrangement;

FIG. 2 is a schematic drawing illustrating an example transceiverarrangement according to some embodiments;

FIGS. 3 a and 3 b are schematic drawings illustrating example frequencytranslated impedances according to some embodiments;

FIGS. 4-9 are schematic drawings illustrating example transceiverarrangements according to some embodiments; and

FIG. 10 is a flowchart illustrating example method steps according tosome embodiments.

DETAILED DESCRIPTION

In the following, embodiments will be described where transceiverstructures are provided comprising a receiver, a transmitter, a signaltransmission and reception arrangement (e.g. an antenna), a transmitfrequency blocking arrangement and a receive frequency blockingarrangement.

The transmitter is connectable to the signal transmission and receptionarrangement node via the receive frequency blocking arrangement and thereceiver is connectable to the signal transmission and receptionarrangement node via the transmit frequency blocking arrangement.

The transmit frequency blocking arrangement is adapted to block passageof transmit frequency signals between the signal transmission andreception arrangement and the receiver.

Blocking of transmit frequency signals may be achieved by the transmitfrequency blocking arrangement having a blocking frequency intervalassociated with the transmit frequency and a non-blocking frequencyinterval associated with the receive frequency. The blocking frequencyinterval may be a frequency interval comprising the transmit frequencyand the non-blocking frequency interval may be a frequency intervalcomprising the receive frequency. The frequency intervals may, forexample, be broad band or narrow band. The frequency intervals may, forexample, comprise all frequencies below a cut-off frequency or allfrequencies of interest above a cut-off frequency.

Similarly, the receive frequency blocking arrangement is adapted toblock passage of receive frequency signals between the signaltransmission and reception arrangement and the transmitter.

Blocking of receive frequency signals may be achieved by the receivefrequency blocking arrangement having a blocking frequency intervalassociated with the receive frequency and a non-blocking frequencyinterval associated with the transmit frequency. The blocking frequencyinterval may be a frequency interval comprising the receive frequencyand the non-blocking frequency interval may be a frequency intervalcomprising the transmit frequency. The frequency intervals may, forexample, be broad band or narrow band. The frequency intervals may, forexample, comprise all frequencies below a cut-off frequency or allfrequencies of interest above a cut-off frequency.

Embodiments described herein provide an active isolator/duplexer betweena transmitter and a receiver. The isolator comprises the transmitfrequency blocking arrangement and the receive frequency blockingarrangement and is tunable by way of frequency translated impedancescomprising a frequency selective impedance and a mixer adapted totranslate the frequency selective impedance by mixing it with a clocksignal. Changing the clock signal frequency provides tuning of theisolator. The possibility to tune the frequency translated impedances toany desirable frequency provides for a possibility to have an integrated(on-chip) implementation of narrowband (high Q-value) frequencyselective impedance, and a single (or very few) implementation maysuffice for covering all relevant frequencies.

Even though many embodiments herein are particularly suitable forintegrated implementation, the isolator may equivalently beimplemented—partly or fully—off-chip (e.g. using discrete components).

FIG. 1 illustrates a typical transceiver arrangement according to theprior art. The typical transceiver comprises a receiver (RX) 120, atransmitter (TX) 130, an antenna 110 and a duplexer 140 implemented as aseparate module. The duplexer provides isolation between the transmitterand the receiver. As mentioned before, such a duplexer implementation istypically expensive and large.

FIG. 2 illustrates an example of an alternative transceiver arrangementaccording to some embodiments. The transceiver arrangement of FIG. 2comprises a receiver (RX) 220, a transmitter (TX) 230, an antenna 210and a transceiver front-end 200. The antenna is connected to an antennanode 211 of the transceiver front-end, the transmitter is connected to atransmitter node 214 of the transceiver front-end, and the receiver isconnected to two receiver nodes 212, 213 of the transceiver front-end(i.e. the receiver has a differential input). In other embodiments, thetransmitter may be connected to two transmitter nodes of the transceiverfront-end (i.e. differential transmitter output) and/or the receiver maybe connected to one receiver node of the transceiver front-end.

The transceiver front-end 200 comprises a transmit frequency blockingarrangement and a receive frequency blocking arrangement.

The transmit frequency blocking arrangement comprises a network ofpassive components 225 comprising at least one transformer 221. In thisexample, the network of passive components consists of the transformer221 only, but in other examples more components may be present. Forexample, the network of passive components could comprise a passivefilter without frequency translation, such as a parallel or seriesLC-circuit. In some embodiments, the network of passive components maycomprise a transformer where the two windings have opposite phase and acoupler connected between the first node of the first side of thetransformer and the first node of the second side of the transformer andadapted to cancel a remaining signal at the blocking frequency interval.

The coupler may comprise first and second resistances connected inseries between the first node of the first side of the transformer andthe first node of the second side of the transformer via a mid pointnode. The coupler may also comprise a third capacitance connectedbetween the mid point node and ground. The resistances may or may not bematched. In some embodiments, the coupler further comprises a thirdinductance connected in parallel with the third capacitance. The thirdcapacitance and the third inductance provides for a possibility to tunethe phase of the coupling between the transformer sides so that theremaining signal is properly canceled.

The transmit frequency blocking arrangement also comprises at least onefrequency translated impedance (FTI) 222, 223, 224 adapted to have ahigher impedance value in a transmit frequency blocking interval (e.g. afrequency interval comprising the transmit frequency) than in anon-blocking frequency interval.

The receive frequency blocking arrangement comprises a network ofpassive components 235 comprising at least one transformer 231. In thisexample, the network of passive components consists of the transformer231 only, but in other examples more components may be present in asimilar manner as described above for the transmit frequency blockingarrangement. The receive frequency blocking arrangement also comprisesat least one frequency translated impedance (FTI) 232, 233, 234 adaptedto have a higher impedance value in a receive frequency blockinginterval (e.g. a frequency interval comprising the receive frequency)than in a non-blocking frequency interval.

Typically, a high impedance value may comprise a value that is higherthan the antenna impedance.

The signal transmission and reception arrangement node 211 is connectedto a first node of a first side of the transformer 221 of the transmitfrequency blocking arrangement and to a first node of a first side ofthe transformer 231 of the receive frequency blocking arrangement.

The frequency translated impedances 222 and 232 are connected to asecond node of the first side of the respective transformer 221, 231,the frequency translated impedances 224 and 234 are connected to a firstnode of the second side of the respective transformer 221, 231, and thefrequency translated impedances 223 and 233 are connected to a secondnode of the second side of the respective transformer 221, 231. Variousimplementations may employ one or more of the FTIs 222, 223 and 224 andone or more of the FTIs 232, 233 and 234.

The transmitter node 214 is connected to the first node of the secondside of the transformer of the receive frequency blocking arrangement,and the receiver node 212 is connected to the first node of the secondside of the transformer of the transmit frequency blocking arrangement.In this example, the receiver has a differential input and two receivernodes. The receiver node 213 is connected to the second node of thesecond side of the transformer of the transmit frequency blockingarrangement. As mentioned before the transmitter may also have adifferential structure and/or the receiver may have a non-differential(single-ended) structure.

FIG. 3 a illustrates an example of a frequency translated impedance(FTI) 300 according to some embodiments. In this example, the FTIcomprises a frequency selective impedance 320 having different values atdifferent frequencies (e.g. a capacitance connected in series to groundmay have a higher impedance value at low frequencies than at highfrequencies), a clock signal provider in the form of a clock signalinput port 310, a mixer 330 and a connection node 340.

The impedance 320 typically has higher impedance in one frequencyinterval than at other frequencies. For example, the impedance may havehigher impedance value at frequencies not exceeding a threshold than atfrequencies exceeding the threshold (hereafter referred to as lowfrequency high value impedance). Alternatively, the impedance may havehigher impedance value at frequencies exceeding threshold than atfrequencies not exceeding the threshold (hereafter referred to as highfrequency high value impedance). Yet alternatively, the impedance mayhave higher impedance value at frequencies in a frequency interval thanat frequencies not in the interval (hereafter referred to as bandfrequency high value impedance). The thresholds may or may not be equal,and are typically—but not necessarily—related to the duplex distance(e.g. threshold value equals half the duplex distance).

The clock signal provider 310 may be a clock signal input port connectedto a clock signal source 315 as illustrated in FIG. 3 a. Alternatively,the clock signal provider may comprise a clock signal generator.

The mixer 330 translates the frequency selective impedance 320 infrequency by mixing it with the clock signal. For example, a lowfrequency high value impedance mixed with the transmit frequency willresult in an impedance having a higher value at frequencies around thetransmit frequency than at other frequencies. Similarly, a highfrequency high value impedance mixed with the transmit frequency willresult in an impedance having a lower value at frequencies around thetransmit frequency than at other frequencies. Yet similarly, a bandfrequency high value impedance (with its frequency interval centeredaround the duplex distance) mixed with the transmit frequency willresult in an impedance having a higher value at frequencies at duplexdistance from the transmit frequency than at other frequencies.

The mixer 330 may be a passive mixer with the frequency selectiveimpedance 320 at the IF port and clocked by the clock signal provider310.

FIG. 3 b illustrates a more detailed example of a frequency translatedimpedance (FTI) 300 b according to some embodiments. In this example,the FTI comprises two frequency selective impedances 321 and 322(typically having the same impedance values). As in FIG. 3 a, theimpedances has different values at different frequencies. The FTI alsocomprises a clock signal provider in the form of a clock signal inputport comprising an in-phase input port 311 and a quadrature input port312, and an IQ-mixer comprising an in-phase mixer 331 and a quadraturemixer 332. The clock signal provider 311, 312 is a IQ clock signal inputport connected to a clock signal source 315 b via an I/Q splitter 316providing a 4-phase IQ clock signal. The outputs from the mixers 331 and332 are provided as an IQ-signal to a connection node comprising anin-phase output port 341 and a quadrature input port 342.

FIG. 4 illustrates an example of a transceiver arrangement according tosome embodiments. The transceiver arrangement of FIG. 4 comprises areceiver (RX) 420, a transmitter (TX) 430, an antenna 410 and atransceiver front-end 400. The antenna is connected to an antenna node411 of the transceiver front-end, the transmitter is connected to atransmitter node 414 of the transceiver front-end, and the receiver isconnected to two receiver nodes 412, 413 of the transceiver front-end(i.e. the receiver has a differential input).

The transceiver front-end 400 comprises a transmit frequency blockingarrangement and a receive frequency blocking arrangement.

The transmit frequency blocking arrangement comprises a transformer 421and a frequency translated impedance (FTI) 422 connected to a secondnode of a first side of the transformer. A first node of the first sideof the transformer is connected to the antenna node, a first node of asecond side of the transformer is connected to one of the receiver nodesand a second node of the second side of the transformer is connected tothe other receiver node. The FTI comprises a low frequency high valueimpedance (LF IMP) 427, a clock signal provider 426 providing a transmitfrequency clock signal (f_(TX)), and a mixer 425. Thus, this FTIimplementation has a high impedance at the transmit frequency and a lowimpedance otherwise (e.g. at the receive frequency). Hence, transmitsignal leakage from the antenna and/or the transmitter will experience ahigh impedance 422. Thereby, the transformer will act as an open circuitand no (or a very limited) current will flow through the first side ofthe transformer 421 and blocking of transmit signals to the receiver isachieved. On the other hand, receive frequency signals will experience alow impedance 422 and the transformer will deliver the receive frequencysignal to the receiver.

The receive frequency blocking arrangement comprises a transformer 431and a frequency translated impedance (FTI) 432 connected to a secondnode of a first side of the transformer. A first node of the first sideof the transformer is connected to the antenna node, a first node of asecond side of the transformer is connected to the transmitter node anda second node of the second side of the transformer is connected toground. The FTI comprises a low frequency high value impedance (LF IMP)437, a clock signal provider 436 providing a receive frequency clocksignal (f_(RX)), and a mixer 435. Thus, this FTI implementation has ahigh impedance at the receive frequency and a low impedance otherwise(e.g. at the transmit frequency). Hence, receive signal leakage from theantenna will experience a high impedance 432. Thereby, the transformerwill act as an open circuit and no (or a very limited) current will flowthrough the first side of the transformer 431 and blocking of receivesignals to the transmitter is achieved. Likewise, receive frequencynoise generated by the transmitter will experience a high impedance 432.Thereby, no (or a very limited) current will flow through the first sideof the transformer 431 and blocking of receive frequency noise from thetransmitter is achieved. On the other hand, transmit frequency signalswill experience a low impedance 432 and the transformer will deliver thetransmit frequency signal to the antenna.

Looking into the circuit from the antenna node 411, the impedance attransmit frequency is low on the transmitter side and the transmittertransformer 431 is coupling transmit frequency signals from thetransmitter to the antenna. On the other hand, looking into the circuitfrom the antenna node 411, the impedance at receive frequency is low onthe receiver side and the receiver transformer 421 is coupling receivefrequency signals from the antenna to the receiver.

FIG. 5 illustrates an example of a transceiver arrangement according tosome embodiments. The transceiver arrangement of FIG. 5 comprises areceiver (RX) 520, a transmitter (TX) 530, an antenna 510 and atransceiver front-end 500. The antenna is connected to an antenna node511 of the transceiver front-end, the transmitter is connected to atransmitter node 514 of the transceiver front-end, and the receiver isconnected to two receiver nodes 512, 513 of the transceiver front-end.The transceiver front-end 500 comprises a transmit frequency blockingarrangement and a receive frequency blocking arrangement.

The transmit frequency blocking arrangement comprises a transformer 521and a frequency translated impedance (FTI) 522. The FTI comprises a highfrequency high value impedance (HF IMP) 527, a clock signal provider 526providing a receive frequency clock signal (f_(RX)), and a mixer 525.Thus, this FTI implementation has a low impedance at the receivefrequency and a high impedance otherwise (e.g. at the transmitfrequency). Hence, the FTI 522 functions similarly as the FTI 422 ofFIG. 4 and the structure of the transmit frequency blocking arrangementis also similar to the one of FIG. 4.

The receive frequency blocking arrangement comprises a transformer 531and a frequency translated impedance (FTI) 532. The FTI comprises a highfrequency high value impedance (HF IMP) 537, a clock signal provider 536providing a transmit frequency clock signal (f_(TX)), and a mixer 535.Thus, this FTI implementation has a low impedance at the transmitfrequency and a high impedance otherwise (e.g. at the receivefrequency). Hence, the FTI 535 functions similarly as the FTI 435 ofFIG. 4 and the structure of the receive frequency blocking arrangementis also similar to the one of FIG. 4.

FIG. 6 illustrates an example of a transceiver arrangement according tosome embodiments. The transceiver arrangement of FIG. 6 comprises areceiver (RX) 620, a transmitter (TX) 630, an antenna 610 and atransceiver front-end 600. The antenna is connected to an antenna node611 of the transceiver front-end, the transmitter is connected to atransmitter node 614 of the transceiver front-end, and the receiver isconnected to two receiver nodes 612, 613 of the transceiver front-end.The transceiver front-end 600 comprises a transmit frequency blockingarrangement and a receive frequency blocking arrangement.

The transmit frequency blocking arrangement comprises a transformer 621and a frequency translated impedance (FTI) 622. The FTI comprises a bandfrequency high value impedance (BF IMP) 627 with high impedance at afrequency corresponding to the duplex distance, a clock signal provider626 providing a receive frequency clock signal (f_(RX)), and a mixer625. Thus, this FTI implementation has a high impedance at the transmitfrequency and a low impedance otherwise (e.g. at the receive frequency).Hence, the FTI 622 functions similarly as the FTI 422 of FIG. 4 and thestructure of the transmit frequency blocking arrangement is also similarto the one of FIG. 4.

The receive frequency blocking arrangement comprises a transformer 631and a frequency translated impedance (FTI) 632. The FTI comprises a bandfrequency high value impedance (BF IMP) 637 with high impedance at afrequency corresponding to the duplex distance, a clock signal provider636 providing a transmit frequency clock signal (f_(TX)), and a mixer635. Thus, this FTI implementation has a high impedance at the receivefrequency and a low impedance otherwise (e.g. at the transmitfrequency). Hence, the FTI 635 functions similarly as the FTI 435 ofFIG. 4 and the structure of the receive frequency blocking arrangementis also similar to the one of FIG. 4.

The band frequency high value impedances 622, 632 may, for example, beimplemented by a parallel LC resonance tank.

FIG. 7 illustrates an example of a transceiver arrangement according tosome embodiments. The transceiver arrangement of FIG. 7 comprises areceiver (RX) 720, a transmitter (TX) 730, an antenna 710 and atransceiver front-end 700. The antenna is connected to an antenna node711 of the transceiver front-end, the transmitter is connected to atransmitter node 414 of the transceiver front-end, and the receiver isconnected to a receiver node 712 of the transceiver front-end (i.e. thereceiver has a non-differential, or single-ended, input).

The transceiver front-end 700 comprises a transmit frequency blockingarrangement and a receive frequency blocking arrangement.

The receive frequency blocking arrangement comprises a transformer 731and a frequency translated impedance (FTI) 732 connected to a secondnode of a first side of the transformer. A first node of the first sideof the transformer is connected to the antenna node via an inductance738, a first node of a second side of the transformer is connected tothe transmitter node and a second node of the second side of thetransformer is connected to ground. The FTI comprises a low frequencyhigh value impedance (LF IMP) 737, a clock signal provider 736 providinga receive frequency clock signal (f_(RX)), and a mixer 735. Thus, thisFTI implementation has a high impedance at the receive frequency and alow impedance otherwise (e.g. at the transmit frequency). Hence, the FTI735 functions similarly as the FTI 435 of FIG. 4.

The transmit frequency blocking arrangement comprises a capacitance 729,an inductance 728 and a frequency translated impedance (FTI) 722. Thecapacitance 729 is connected between the antenna and the inductance 728,which in turn is connected between the capacitance 729 and the receivernode 712. The FTI is connected at a node between the capacitance 729 andthe inductance 728. The FTI comprises a low frequency high valueimpedance (LF IMP) 727, a clock signal provider 726 providing a receivefrequency clock signal (f_(RX)), and a mixer 725. Thus, this FTIimplementation has a high impedance at the receive frequency and a lowimpedance otherwise (e.g. at the transmit frequency). Hence, transmitsignal leakage from the antenna and/or the transmitter will experience alow impedance 722. Thereby, (almost) all current will flow through theimpedance 722 and blocking of transmit signals to the receiver isachieved. On the other hand, receive frequency signals will experience ahigh impedance 722 and the current from the antenna will flow throughthe inductance 728, delivering the receive frequency signal to thereceiver.

The inductance 738 and the capacitance 729 form an L-match network asseen from the transformer 731 of the receive frequency blockingarrangement and the components may be chosen to provide a band-passfilter associated with the transmit frequency. Hence, the transmittersignal to the antenna is filtered by this structure, thus attenuatingthe harmonic content of the transmitter signal. Some attenuation ofreceive frequency noise from the transmitter is also achieved. Theinductance 728 and the capacitance 729 form a series resonance circuit.The components may be chosen so that the resonance frequency is thereceive frequency to further simplify passage of receive frequencysignals.

One advantage of this embodiment is that transmit frequency signalvoltage across both of the FTIs 722 and 732 is kept at low values,reducing device voltage stress and simplifying mixer design.

FIG. 8 illustrates an example of a transceiver arrangement according tosome embodiments. The transceiver arrangement of FIG. 8 comprises aplurality of receivers (RX) 820 a-c typically serving differentfrequency bands, a transmitter (TX) 830, an antenna 810 and atransceiver front-end 800. The antenna is connected to an antenna node811 of the transceiver front-end, and the transmitter is connected to atransmitter node 814 of the transceiver front-end. The receivers areconnected to a receiver node 812 of the transceiver front-end viarespective SAW filters 828 a-c and an antenna switch 829.

The transceiver front-end 800 comprises a receive frequency blockingarrangement.

The receive frequency blocking arrangement comprises a transformer 831and a frequency translated impedance (FTI) 832 connected to a secondnode of a first side of the transformer. A first node of the first sideof the transformer is connected to the antenna node, a first node of asecond side of the transformer is connected to the transmitter node anda second node of the second side of the transformer is connected toground. The FTI comprises a low frequency high value impedance (LF IMP)837, a clock signal provider 836 providing a receive frequency clocksignal (f_(RX)), and a mixer 835. Hence, the FTI 835 functions similarlyas the FTI 435 of FIG. 4.

The transmit frequency blocking arrangement comprises the antenna switch829 and the SAW-filters 828 a-c. Thus, FIG. 8 illustrates an embodimentwhere a conventional solution is used for the transmit frequencyblocking arrangement. The transceiver front-end 800 may be combined withany suitable known or future transmit frequency blocking arrangement.

One advantage with the implementation of FIG. 8 is that leakage towardsthe receiver at transmit frequency can be suppressed in the same orderas with a conventional duplex filter, which may not be possible with theFTI construction for all duplex distances and frequency bands.

FIG. 9 illustrates an example of a transceiver arrangement according tosome embodiments. The transceiver arrangement of FIG. 9 comprises aplurality of transmitters (TX) 930 a-c typically serving differentfrequency bands, a receiver (RX) 920, an antenna 910 and a transceiverfront-end 900. The antenna is connected to an antenna node 911 of thetransceiver front-end, and the receiver is connected to two receivernodes 912, 913 of the transceiver front-end. The transmitters areconnected to a transmitter node 914 of the transceiver front-end viarespective SAW filters 938 a-c and an antenna switch 939.

The transceiver front-end 900 comprises a transmit frequency blockingarrangement.

The transmit frequency blocking arrangement comprises a transformer 921and a frequency translated impedance (FTI) 922 connected to a secondnode of a first side of the transformer. A first node of the first sideof the transformer is connected to the antenna node, a first node of asecond side of the transformer is connected to one of the receiver nodesand a second node of the second side of the transformer is connected tothe other receiver node. The FTI comprises a low frequency high valueimpedance (LF IMP) 927, a clock signal provider 926 providing a transmitfrequency clock signal (f_(TX)), and a mixer 925. Hence, the FTI 922functions similarly as the FTI 422 of FIG. 4.

The receive frequency blocking arrangement comprises the antenna switch939 and the SAW-filters 938 a-c. Thus, FIG. 9 illustrates an embodimentwhere a conventional solution is used for the receive frequency blockingarrangement. The transceiver front-end 900 may be combined with anysuitable known or future receive frequency blocking arrangement.

One advantage with the implementation of FIG. 9 is that transmitternoise at receive frequency can be suppressed in the same order as with aconventional duplex filter, which may not be possible with the FTIconstruction for all duplex distances and frequency bands.

Some embodiments comprise combinations of the examples illustrated inFIG. 4-9. For example, the transmit frequency blocking arrangement ofFIG. 6 may be combined with the receive frequency blocking arrangementof FIG. 4, the transmit frequency blocking arrangement of FIG. 4 may becombined with the receive frequency blocking arrangement of FIG. 6, etc.

In some embodiments, a transmit frequency blocking arrangement or areceive frequency blocking arrangement as described above may becombined with a receive frequency blocking arrangement or a transmitfrequency blocking arrangement respectively, where the FTI is replacedby a filter arrangement adapted to have a higher impedance value in theblocking frequency interval than in the non-blocking frequency interval.

The filter arrangement may comprise a first inductance connected inparallel with a first capacitance to form a blocking frequency resonancearrangement.

The filter arrangement may further comprise at least one of a secondinductance and a second capacitance connected in series with theblocking frequency resonance arrangement to form a non-blockingfrequency resonance arrangement.

If the filter arrangement is a low pass filter arrangement, the filterarrangement comprises the second capacitance. If the filter arrangementis a high pass filter arrangement, the filter arrangement may comprisethe second inductance.

FIG. 10 illustrates an example method 1000 of blocking transmit and/orreceive frequency signals according to some embodiments. The methodstarts in 1010, where it is determined whether it is transmit or receivefrequency signals that are to be blocked.

If transmit frequency signals are to be blocked a suitable frequencyselective impedance is selected in 1020 and a corresponding translationfrequency is selected in 1030. In 1040, an FTI is constructed using theselected impedance, a clock signal provider having the translationfrequency, and a mixer that translates the impedance using thetranslation frequency. The selections in 1020 and 1030 are related ashas been exemplified above in connection to e.g. FIGS. 4-6 and maytypically be chosen to provide an FTI with high impedance at transmitfrequency and low impedance at receive frequency. In 1050, a signaltransmission and reception arrangement (e.g. an antenna) is connected toa first node of a first side of a transformer and a receiver isconnected to a first node of a second side of the transformer. Thefrequency translated impedance is connected to a second node of thefirst side of the transformer in 1060.

If receive frequency signals are to be blocked a suitable frequencyselective impedance is selected in 1021 and a corresponding translationfrequency is selected in 1031. In 1041, an FTI is constructed using theselected impedance, a clock signal provider having the translationfrequency, and a mixer that translates the impedance using thetranslation frequency. The selections in 1021 and 1031 are related ashas been exemplified above in connection to e.g. FIGS. 4-6 and maytypically be chosen to provide an FTI with high impedance at receivefrequency and low impedance at transmit frequency. In 1051, a signaltransmission and reception arrangement (e.g. an antenna) is connected toa first node of a first side of a transformer and a receiver isconnected to a first node of a second side of the transformer. Thefrequency translated impedance is connected to a second node of thefirst side of the transformer in 1061.

Other details of the method may be extracted from the transceiverembodiments described above.

The described embodiments and their equivalents may be realized inhardware. They may be performed by specialized circuits such as forexample application-specific integrated circuits (ASIC), by discretecomponents, or by a combination thereof. All such forms are contemplatedto be within the scope of the invention.

The invention may be embodied within an electronic apparatus (such as awireless or wired communication device) comprising circuitry/logicaccording to any of the embodiments. The electronic apparatus may, forexample, be a portable or handheld mobile radio communication equipment,a mobile radio terminal, a mobile telephone, a base station, acommunicator, an electronic organizer, a smartphone, a computer, anotebook, or a mobile gaming device.

The invention has been described herein with reference to variousembodiments. However, a person skilled in the art would recognizenumerous variations to the described embodiments that would still fallwithin the scope of the invention. For example, the method embodimentsdescribed herein describes example methods through method steps beingperformed in a certain order. However, it is recognized that thesesequences of events may take place in another order without departingfrom the scope of the invention. Furthermore, some method steps may beperformed in parallel even though they have been described as beingperformed in sequence.

In the same manner, it should be noted that in the description ofembodiments, the partition of functional blocks into particular units isby no means limiting to the invention. Contrarily, these partitions aremerely examples. Functional blocks described herein as one unit may besplit into two or more units. In the same manner, functional blocks thatare described herein as being implemented as two or more units may beimplemented as a single unit without departing from the scope of theinvention.

Hence, it should be understood that the limitations of the describedembodiments are merely for illustrative purpose and by no meanslimiting. Instead, the scope of the invention is defined by the appendedclaims rather than by the description, and all variations that fallwithin the range of the claims are intended to be embraced therein.

1-22. (canceled)
 23. A transceiver front-end of a communication deviceconnectable: at a signal transmission and reception arrangement node toa signal transmission and reception arrangement configured to transmit atransmit signal having a transmit frequency and to receive a receivesignal having a receive frequency; at one or more transmitter nodes to atransmitter configured to produce the transmit signal; and at one ormore receiver nodes to a receiver configured to process the receivesignal; the transceiver front-end comprising at least one of: a transmitfrequency blocking arrangement, connected to the signal transmission andreception arrangement node and at least one of the transmitter nodes,having a blocking frequency interval associated with the transmitfrequency and a non-blocking frequency interval associated with thereceive frequency, and configured to block passage of transmit frequencysignals between the signal transmission and reception arrangement andthe receiver; and a receive frequency blocking arrangement, connected tothe signal transmission and reception arrangement node and at least oneof the receiver nodes, having a blocking frequency interval associatedwith the receive frequency and a non-blocking frequency intervalassociated with the transmit frequency, and configured to block passageof receive frequency signals between the signal transmission andreception arrangement and the transmitter; wherein at least one of thetransmit frequency blocking arrangement and the receive frequencyblocking arrangement comprises: a network of passive componentscomprising at least one transformer; and a frequency translatedimpedance configured to have a higher impedance value in the blockingfrequency interval than in the non-blocking frequency interval.
 24. Thetransceiver front-end of claim 23 wherein the frequency translatedimpedance comprises: a frequency selective impedance; a clock signalcircuit configured to provide a clock signal; and a mixer circuitconfigured to translate the frequency selective impedance by mixing itwith the clock signal.
 25. The transceiver front-end of claim 23 whereinthe frequency translated impedance of the receive frequency blockingarrangement is configured to have a higher impedance value at thereceive frequency than at the transmit frequency.
 26. The transceiverfront-end of claim 23 wherein the signal transmission and receptionarrangement node is connected to a first node of a first side of thetransformer of the receive frequency blocking arrangement, the frequencytranslated impedance of the receive frequency blocking arrangement is afirst frequency translated impedance and is connected to a second nodeof the first side of the transformer of the receive frequency blockingarrangement, and a first node of the one or more transmitter nodes isconnected to a first node of the second side of the transformer of thereceive frequency blocking arrangement.
 27. The transceiver front-end ofclaim 24 wherein the frequency selective impedance of the receivefrequency blocking arrangement is an impedance having higher impedancevalue at frequencies not exceeding a first threshold than at frequenciesexceeding the first threshold and the clock signal has the receivefrequency.
 28. The transceiver front-end of claim 24 wherein thefrequency selective impedance of the receive frequency blockingarrangement is an impedance having higher impedance value at frequenciesexceeding a threshold than at frequencies not exceeding the thresholdand the clock signal has the transmit frequency.
 29. The transceiverfront-end of claim 24 wherein the frequency selective impedance of thereceive frequency blocking arrangement is an impedance having higherimpedance value at frequencies in a first interval than at frequenciesnot in the first interval and the clock signal has the transmitfrequency.
 30. The transceiver front-end of claim 24 wherein the receivefrequency blocking arrangement comprises a second frequency translatedimpedance connected to the first node of the second side of thetransformer of the receive frequency blocking arrangement.
 31. Thetransceiver front-end of claim 30 wherein a second node of the secondside of the transformer of the receive frequency blocking arrangement isconnected to one or more of: a third frequency translated impedance; anda second node of the one or more transmitter nodes.
 32. The transceiverfront-end of claim 23 wherein the frequency translated impedance of thetransmit frequency blocking arrangement is configured to have a higherimpedance value at the transmit frequency than at the receive frequency.33. The transceiver front-end of claim 31 wherein the signaltransmission and reception arrangement node is connected to a first nodeof a first side of the transformer of the transmit frequency blockingarrangement, the frequency translated impedance of the transmitfrequency blocking arrangement is a fourth frequency translatedimpedance and is connected to a second node of the first side of thetransformer of the transmit frequency blocking arrangement, and a firstnode of the one or more receiver nodes is connected to a first node ofthe second side of the transformer of the transmit frequency blockingarrangement.
 34. The transceiver front-end of claim 24 wherein thefrequency selective impedance of the transmit frequency blockingarrangement is an impedance having higher impedance value at frequenciesnot exceeding a threshold than at frequencies exceeding the thresholdand the clock signal has the transmit frequency.
 35. The transceiverfront-end of claim 24 wherein the frequency selective impedance of thetransmit frequency blocking arrangement is an impedance having higherimpedance value at frequencies exceeding a threshold than at frequenciesnot exceeding the threshold and the clock signal has the receivefrequency.
 36. The transceiver front-end of claim 24 wherein thefrequency selective impedance of the transmit frequency blockingarrangement is an impedance having higher impedance value at frequenciesin an interval than at frequencies not in the interval and the clocksignal has the receive frequency.
 37. The transceiver front-end of claim35 wherein the transmit frequency blocking arrangement comprises a fifthfrequency translated impedance connected to the first node of the secondside of the transformer of the transmit frequency blocking arrangement.38. The transceiver front-end of claim 37 wherein a second node of thesecond side of the transformer of the transmit frequency blockingarrangement is connected to one or more of: a sixth frequency translatedimpedance; and a second node of the one or more receiver nodes.
 39. Thetransceiver front-end of claim 27 wherein the receive frequency blockingarrangement comprises a first inductance connected between the signaltransmission and reception arrangement node and the first node of thefirst side of the transformer of the receive frequency blockingarrangement and wherein the transmit frequency blocking arrangementcomprises: a capacitance connected to the signal transmission andreception arrangement node at a first node and configured to form amatching network for transmit signals with the first inductance; asecond inductance connected between a second node of the capacitance anda first node of the one or more receiver nodes and configured to form aseries resonance circuit for receive signals with the capacitance; and afrequency translated impedance connected to the second node of thecapacitance and comprising a frequency selective impedance having higherimpedance value at frequencies not exceeding a second threshold than atfrequencies exceeding the second threshold, a clock signal circuitconfigured to provide a clock signal having the receive frequency and amixer circuit configured to translate the frequency selective impedanceby mixing it with the clock signal.
 40. A transceiver comprising: atransceiver front-end connectable: at a signal transmission andreception arrangement node to a signal transmission and receptionarrangement configured to transmit a transmit signal having a transmitfrequency and to receive a receive signal having a receive frequency; atone or more transmitter nodes to a transmitter configured to produce thetransmit signal; and at one or more receiver nodes to a receiverconfigured to process the receive signal; the transceiver front-endcomprising at least one of: a transmit frequency blocking arrangement,connected to the signal transmission and reception arrangement node andat least one of the transmitter nodes, having a blocking frequencyinterval associated with the transmit frequency and a non-blockingfrequency interval associated with the receive frequency, and configuredto block passage of transmit frequency signals between the signaltransmission and reception arrangement and the receiver; and a receivefrequency blocking arrangement, connected to the signal transmission andreception arrangement node and at least one of the receiver nodes,having a blocking frequency interval associated with the receivefrequency and a non-blocking frequency interval associated with thetransmit frequency, and configured to block passage of receive frequencysignals between the signal transmission and reception arrangement andthe transmitter; wherein at least one of the transmit frequency blockingarrangement and the receive frequency blocking arrangement comprises: anetwork of passive components comprising at least one transformer; and afrequency translated impedance configured to have a higher impedancevalue in the blocking frequency interval than in the non-blockingfrequency interval; the transmitter; and the receiver.
 41. Thetransceiver of claim 40 further comprising the signal transmission andreception arrangement.
 42. A communication device comprising atransceiver, wherein the transceiver comprises a transceiver front-endconnectable: at a signal transmission and reception arrangement node toa signal transmission and reception arrangement configured to transmit atransmit signal having a transmit frequency and to receive a receivesignal having a receive frequency; at one or more transmitter nodes to atransmitter configured to produce the transmit signal; and at one ormore receiver nodes to a receiver configured to process the receivesignal; the transceiver front-end comprising at least one of: a transmitfrequency blocking arrangement, connected to the signal transmission andreception arrangement node and at least one of the transmitter nodes,having a blocking frequency interval associated with the transmitfrequency and a non-blocking frequency interval associated with thereceive frequency, and configured to block passage of transmit frequencysignals between the signal transmission and reception arrangement andthe receiver; and a receive frequency blocking arrangement, connected tothe signal transmission and reception arrangement node and at least oneof the receiver nodes, having a blocking frequency interval associatedwith the receive frequency and a non-blocking frequency intervalassociated with the transmit frequency, and configured to block passageof receive frequency signals between the signal transmission andreception arrangement and the transmitter; wherein at least one of thetransmit frequency blocking arrangement and the receive frequencyblocking arrangement comprises: a network of passive componentscomprising at least one transformer; and a frequency translatedimpedance configured to have a higher impedance value in the blockingfrequency interval than in the non-blocking frequency interval; thetransmitter; and the receiver.
 43. A method of blocking transmitfrequency signals from passage between a signal transmission andreception arrangement and a receiver of a communication device,comprising: constructing a frequency translated impedance comprising afrequency selective impedance, a mixer circuit and a clock signalcircuit, wherein the frequency translated impedance has a higherimpedance value at the transmit frequency than at the receive frequency;connecting the signal transmission and reception arrangement to a firstnode of a first side of a transformer and the receiver to a first nodeof a second side of the transformer; and connecting the frequencytranslated impedance to a second node of the first side of thetransformer.
 44. A method of blocking receive frequency signals frompassage between a signal transmission and reception arrangement and atransmitter of a communication device, comprising: constructing afrequency translated impedance comprising a frequency selectiveimpedance, a mixer circuit and a clock signal circuit, wherein thefrequency translated impedance has a higher impedance value at thereceive frequency than at the transmit frequency; connecting the signaltransmission and reception arrangement to a first node of a first sideof a transformer and the transmitter to a first node of a second side ofthe transformer; and connecting the frequency translated impedance to asecond node of the first side of the transformer.